246 AQUATIC MICROSCOPY FOR BEGINNERS. 



shown in Fig. 176. I have collected them late in the 

 fall, and, keeping them in a small aquarium in a warm 

 room, have had them hatch out in November. The 

 young fastened themselves to the sides of the glass 

 bowl, where they appeared like delicate grains of 

 translucent pearl. There was no jelly at this early 

 stage, and each little Pectinatella stood alone, conse- 

 quently all the internal organs were even more dis- 

 tinctly visible than usual through their hyaline bodies. 

 I hoped to see them develop into colonies, but the sur- 

 roundings were not entirely favorable, perhaps the 

 proper food was not attainable, so they died. 



Each mature polyzoan has from fifty to eighty ten,- 

 tacles. 



2. Cristat^lla. 



The form and movements of Cristatella have already 

 been referred to on a preceding page. The young 

 colonies are rounded, and are found in the same local- 

 ities with Pectinatella. The statoblasts are circular 

 and have two rows of double hooks, one row around 

 the border, the other nearer the center (Fig. 177). 

 The hooks are not simple as in those of Pectinatella, 

 but have several branches at the top of the stem, and 

 the tips are forked. 



According to the writer's experience, Cristatella is 

 not common. 



3. L6PH0PUS. 



A species of Lophopus has been found in California 

 and the same form has been obtained by the writer in 

 a small pond on the Pennsylvania side of the Delaware 

 River opposite Trenton, N. J. It has not been re- 



